Wireless
sensor networks (WSNs) consist of numerous nodes gathering observations and
combining these observations. Often, the timing of these observations is of
importance when processing sensor data. Thus, a need for clock synchronization
arises in WSNs. The clock sampling mutual network synchronization (CS-MNS)
algorithm has been proposed to fulfill this role.
Analytical
results are given that show, in the absence of initial offset errors, that the
network clocks converge. In the general case, conditions are presented under
which the clock rates show convergent behaviour. The CS-MNS algorithm is
improved through the addition of a bias term to control initial divergence.
Numerical
simulation is used to explore the behaviour of CS-MNS for different network
topologies. The CS-MNS algorithm is implemented under TinyOS and its
performance experimentally evaluated. The results show that CS-MNS behaves as
predicted by analysis and simulation, and achieves significantly better clock
synchronization performance than the flooding time synchronization protocol
(FTSP).